The use of cars and freight trucks as our primary land transportation system is prone to traffic jams and accidents that take a fair toll of life, productivity and energy resources. This is so because while we keep building new roads there are usually more cars and trucks than the roads can handle, petroleum is a limited resource and above all because the system is obsolete in many ways since it still relies on traffic signals and the ability of people to drive their cars and trucks as it has been for the past one hundred years. There are also other economic issues and environmental concerns that question the use of cars and trucks as our primary transportation option. Even when collective transportation is constantly improving people still prefer a personal transportation vehicle that takes them anywhere they want.
In the U.S. the Intelligent Transportation Systems initiative or ITS (www.itsa.org) promotes the development and implementation of new technologies to allow for automated driving and indeed improve the efficiency and safety of personal transportation and freight delivery using cars and trucks. So far it has proven very costly and difficult to do so. The main flaw of the ITS initiative is assuming that the primary vehicle for automated personal transportation and freight delivery will still be a car and a freight truck when it looks like it is more complex and costly adapting a car and a truck to this concept as cars and trucks are meant to be driven than developing and implementing a totally new fully automated personal transportation and freight delivery system from the start.
A transportation system of automated vehicles that run on steel tracks and other custom built guide ways in use today at several locations is known as Personal Rapid Transit (PRT) (http://en.wikipedia.org/wiki/personal_rapid_transit). It is not a reliable or efficient personal transportation and freight delivery alternative to a car and a freight truck because such vehicles only go from one station to another as a collective transportation system does and the only similarity to a personal transportation system is that people can travel in a private vehicle. Another drawback of current PRT is that you could end up waiting in line for a long time until a vehicle is available to pick you up.
In U.S. Pat. No. 3,118,392 Zimmerman proposes a transportation system of self-propelled individual vehicles that automatically move from station to station using an overhead guideway. As with PRT his proposal is not a reliable or efficient personal transportation and freight delivery alternative to a car and a truck because the vehicles only go from one station to another as a collective transportation system does. As the system must rely on switching devices at the guide way and moving parts at a motorized carriage to engage and activate the switching devices so as to direct a vehicle to a destination it is not a practical proposition for a fast speed high volume transportation system of vehicles that could go on their own anywhere a track can take them.
A square shaped enclosed guideway makes it difficult to provide maintenance to the inside of the guideway and have access to the motorized carriages; furthermore, the flanges that support the wheels of the carriages could bend under heavy loads and as the thickness of the guideway is increased to prevent this then the guideway could become too heavy for all practical purposes. Motorized carriages moving inside the guideway will result in high levels of friction, noise and heat that will require additional control mechanisms and mechanical contacts between the motorized carriage and the guideway for positioning the carriage within the guideway channel particularly when each carriage will have at least two front and two rear wheels to support the vehicles weight.
In U.S. Pat. No. 3,987,734 Horn proposes a transportation system that features modules for carrying passengers and freight from station to station attached to a conveyor and there's a transfer device to load and unload vehicles into the conveyors. It is obvious that this proposal is not a practical personal transportation and freight delivery alternative to a car and a truck either because the vehicles can only go from one station to another and then the system depends on additional devices and a complex procedure to divert vehicles from one track to another and the vehicles will have to wait in line to do so; furthermore, as such vehicles have no propulsion of their own if the conveyor breaks down the complete system is stalled.
In U.S. Pat. No. 5,074,220 Petersen proposes an overhead rapid transit system using a tubular enclosed guideway and self-propelled vehicles with a steering mechanism and in-line wheels. The main drawback of this proposal is the guideway configuration for several reasons: 1—In the preferred embodiment it will only allow vehicles to do either right or left turns at guideway splits but not both depending on which side of the guideway an offset open slot is provided. 2—In the preferred embodiment the wheels of the motorized carriage or trolley will have to cross over the guideway slot at splits causing the vehicle to bounce and vibrate. 3—Any of the embodiment alternatives will require additional control mechanisms and mechanical contacts within the guideway and the motorized carriage or trolley for steering the vehicle and keeping it stabilized at guideway splits as the concave wheels track is no longer present at those guideway segments.
An enclosed guideway as noted makes it difficult to provide maintenance to the inside of the guideway and have access to the motorized carriage or trolley; furthermore, the bottom wall of the guideway that supports the wheels of the motorized carriage or trolley could bend under heavy loads and as the thickness of the guideway is increased to prevent this then the guideway could become too heavy for all practical purposes. A wheel with rounded traction rolling inside a concave track within an enclosed guideway and additional mechanical contacts between the vehicle and the guideway for steering and stability will result in high levels of friction, noise, heat, wear and tear.
In U.S. Pat. No. 6,202,566 Hutchinson proposes a high-speed high-capacity transportation system using an overhead guideway and wheeled motive modules with a steering mechanism that ride within the guideway channel to carry payloads. It is not a reliable or efficient personal transportation alternative to a car because a passengers carriage is considered payload too. It is obvious from the Patent Drawings and the Detailed Description of the Invention that it will be very difficult to keep the payload stable as it travels to its destination and for the same reason to do it at high speeds. Since the wheeled motive modules is generally much smaller than the payload units these must be positioned further apart from each other for safety reasons and as a result less of them will fit inside a track section as it should for optimal performance.
As with the Zimmerman Patent a square shaped enclosed guideway makes it difficult to provide maintenance to the inside of the guideway and have access to the wheeled motive modules; furthermore, the flange that supports the modules could bend under heavy loads and as the thickness of the guideway is increased to prevent this then the guideway could become too heavy for all practical purposes. Wheeled motive modules inside an enclosed guideway will result in high levels of friction, noise and heat that will require additional control mechanisms and mechanical contacts between the vehicle and the guideway for positioning the motive modules within the channel particularly when each carriage will have at least two front and two rear wheels to support the vehicles weight. Another drawback of this proposal is that at the guideway forks the wheeled motive modules have to ride over a slot through which a payload-holding flange must pass causing the vehicles to bounce and vibrate.
In U.S. Pat. No. 7,124,692 Guenther, et al. proposes an overhead high speed mass transit passenger and freight transportation system that will operate as an overhead suspended light rail (train). It is meant to operate as a collective transportation system does and not as a personal transportation and freight delivery system and as such vehicles only go from one station to another and the system must rely on track switches to route vehicles to a station as vehicles have no steering mechanism to get to a destination on their own.
Other important features that a reliable and efficient automated personal transportation and freight delivery system should have and seems to be missing in the prior art are: 1—A way to fit into a track section as many vehicles as it can hold moving at high speeds in a safe manner to improve performance. 2—A way to allow vehicles to go from a higher track section to a lower one and vice versa in a short linear track section. 3—A way to allow vehicles to travel high into a building. 4—A way to remove disabled vehicles from track sections.